Intravital Imaging of Neutrophil Recruitment Reveals the Efficacy of FPR1 Blockade in Hepatic Ischemia- Reperfusion Injury
Intravital Imaging of Neutrophil Recruitment Reveals the Efficacy of FPR1 Blockade in Hepatic Ischemia- Reperfusion Injury
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DOI：
10.4049/jimmunol.1601773
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发表时间：
2017-02-15
影响因子：
4.4
通讯作者：
Inomata, Yukihiro
中科院分区：
文献类型：
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作者：
Honda, Masaki;Takeichi, Takayuki;Inomata, Yukihiro
中性粒细胞被认为是由肝缺血-再灌注（I/R）损伤引起的病理生理变化的原因，所述肝缺血-再灌注损伤是创伤、休克、肝切除和移植的并发症。最近，越来越多的证据表明，甲酰肽受体（FPR）信号传导构成了一个重要的危险信号，引导中性粒细胞的炎症部位。本研究旨在研究在肝I/R期间使用双光子激光扫描显微镜（TPLSM）对FPR 1阻断的动态中性粒细胞募集。对LysM-eGFP小鼠进行部分热肝I/R。用FPR1拮抗剂环孢菌素H（CsH）或甲酰肽fMLF对其进行预处理。使用TPLSM技术在肝脏激光照射或I/R后对肝脏进行成像。CsH治疗减轻肝I/R损伤，如血清转氨酶水平降低，肝细胞坏死/凋亡减少，炎性细胞因子，趋化因子和氧化应激减少所证明的。相比之下，全身给予fMLF几乎没有效果。时间推移TPLSM显示，FPR 1阻断抑制中性粒细胞在体内激光照射诱导的坏死区的积聚。CsH治疗组非灌注区中性粒细胞数和爬行速度均低于对照组。同时，FPR1阻断不影响单核细胞/巨噬细胞募集。肝脏I/R促进中性粒细胞的保留和他们在脾脏中的活跃行为，而CsH治疗阻止他们的变化。活体TPLSM显示，甲酰基肽-FPR 1信号传导负责调节中性粒细胞趋化性，以允许迁移到肝I/R中的坏死区域。我们的研究结果为阐明肝I/R中免疫细胞反应的机制提供了有效的方法。
Neutrophils are considered responsible for the pathophysiological changes resulting from hepatic ischemia- reperfusion (I/R) injury, which is a complication of trauma, shock, liver resection, and transplantation. Recently, evidence is accumulating that formylpeptide receptor (FPR) signaling constitutes an important danger signal that guides neutrophils to sites of inflammation. This study aimed to investigate dynamic neutrophil recruitment using two-photon laser- scanning microscopy (TPLSM) in response to FPR1 blockade during hepatic I/R. LysM- eGFP mice were subjected to partial warm hepatic I/R. They were pretreated with an FPR1 antagonist, cyclosporine H (CsH), or formyl peptide, fMLF. Liver was imaged after hepatic laser irradiation or I/R using the TPLSM technique. CsH treatment alleviated hepatic I/R injury, as evidenced by decreased serum transaminase levels, reduced hepatocyte necrosis/apoptosis, and diminished inflammatory cytokine, chemokine, and oxidative stress. In contrast, systemic administration of fMLF showed few effects. Time- lapse TPLSM showed that FPR1 blockade inhibited the accumulation of neutrophils in the necrotic area induced by laser irradiation in vivo. In the CsH-treated I/R group, the number and crawling velocity of neutrophils in the nonperfused area were lower than those in the control group. Meanwhile, FPR1 blockade did not affect monocyte/macrophage recruitment. Hepatic I/R promoted the retention of neutrophils and their active behavior in the spleen, whereas CsH treatment prevented their changes. Intravital TPLSM revealed that formyl- peptide-FPR1 signaling is responsible for regulating neutrophil chemotaxis to allow migration into the necrotic area in hepatic I/R. Our findings suggest effective approaches for elucidating the mechanisms of immune cell responses in hepatic I/R.